Shaping machine



Sept. 29, 1942. F, WEGERDT smrme MACHINE Filed Aug. 19, 1937 15 Sheets-Sheet 1 Sept. 29, 1942. F. WEGERDT V SHAPING MACHINE Filed Aug. 19, 1.937

15 Sheets-Sheet 2 Sept. 29, 1942- F. WEGERDT 2,297,268

SHAPING MACHINE Filed Aug. 19, 1937 15 Sheets-Sheet 5 jjza'ezaz ar: Ffifz W e fie n1 2 A Z l orre J Sept. 29, 1942. F. WEGERDT 2,297,268

SHAPING MACHINE Filed Aug. 19, 1937 15 Sheets-Sheet 4 15 Sheets-Sheet 5 jjwazzior: Fr-ZZ Z Weaer b/Z B o w I AZ Z o/me s F. WEGERDT O O O O kw J l Hn n fifl ,SHAPING MACHINE.

Filed Aug. 19, 1937 Sept. 29, 1942.

Sept. 29', 1942. F. WEGERDT SHAPING MACHINE Filed Aug. 19, 1937 15 Sheets-Sheet 9 Sept. 29, 1942..- F. WEGERDT SHAPING MACHINE Filed Aug. 19, 1937 15 Sheets-Sheet 10 Sept. 29, 1942. F. WEGERDT SHAPING MACHINE Filed Aug. 19, 1937 15 Sheets-Sheet l] AZZorrreyw F. WEGERDT 2,297,268

SHAPING MACHINE} Filed Aug. 19, 1937 15 Sheets-Sheet 12 .bzz/ezaiorr 6 w M M w# A +1 Sept. 29, 1942.

15 Sheets-Sheet 15 F. WEGERDT SHAPING MACH INE Filed Aug. 19, 1937 Sept. 29, 194 2.

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Patented Sept. 29, 1942 UNHTED STATES FATENT OFFICE SHAPING MACHINE Application August 19, 1937, Serial No. 159,952 In Germany August 22, 1936 10 Claims.

The invention relates to a shaping machine, the tool holder slide of which is reciprocable transversely to the planing direction.

It is an object of the invention, in shaping machines the tool holder slide of which is reciprocable transversely to the planing direction, to drive the tool holder hydraulically and connect the pump and the control device of the hydraulic driving arrangement rigidly with the tool holder slide. It has been found that the pump and the control device, when suitably selected and arranged, may be rigidly connected to the tool holder slide without difficulty.

Further objects will be apparent from the following description and drawings.

Two embodiments of the invention are illustrated by way of examples in the accompanying drawings, in which:

Fig. 1 is a side view of a shaping machine according to the invention,

Fig. 2 is a side view showing the casing for the hydraulic driving aggregate.

Fig. 3 is a plan view of the tool holder with its slide.

Fig. 4 is a front view of the machine, showing the twin arrangement with two tool holder slides.

Fig. 5 is a rear view of the machine.

Fig. 6 is a longitudinal sectional view through the casing of Fig. 2.

Fig. 7 is a sectional view through the casing taken on line VII-VII of Fig. 6.

Fig. 8 is a sectional view taken on line VIII VIII of Fig. 7.

Fig. 9 is a sectional view showing certain parts of Figs. '7 and 8 in side elevation as seen in the direction of the arrow 11-2; of Fig. 7.

Fig. 10 is a sectional view taken on the line XX of Fig. '7.

Fig. 11 is a longitudinal section through the rotary piston pump of the hydraulic drive.

of the shaping machine as seen from the outside in the direction of the arrow of Fig. 19. Fig. 19 is a plan View of the slide of Fig. 18.

Fig. 20 is a section taken on line XXXX of Fig. 18.

Fig. 21 is a section of Fig. 19.

Fig. 22 is a section taken on line XXII-XXII of Figs. 19 and 20.

Fig. 23 is a section taken on line XXIIIXXIII of Figs. 19 and 20.

In a shaping machine, i. e. a, planing machine, the tool of which is located on a reciprocable holder, the advance movement transversely to the direction of movement of the tool holder is usually accomplished by th table on which the Work piece is fixed. For numerous working operations it has however also been found advantageous to use a stationary table as work piece carrier, and to create the feed movement and the high-speed movement by moving the tool holder with the tool in a slide which is displaceable transversely to the direction of movement of the tool holder. Such shaping machines are frequently manufactured with twin tool holder slides, which are reciprocable transversely to the planing direction. In machines of this kind the slides of two tool holders are arranged in such a manner that they can be displaced along a common support, on which also the tables (there are usually two tables also) to which the work piece is clamped are fixed.-

Such machines are particularly used for machining large and bulky pieces. Besides the usual requirement in machine tools of extremely exact and fine working, it is of very great importance that the machine may be utilised with high efficiency. The known shaping machines with tool holder slides which are reciprocable transversely to the planing direction fulfil these requirements only to an insufiicient degree, so that it is necessary to make concessions as to efiiciency of utilization in order to secure the required necessary exactness of working.

Although it has been known for a long time that shaping machines, in which the feed and the high-speed movements are caused by the table, can be driven hydraulically with great advantage, shaping machines the tool holder slides of which are moved transversely to the planing direction have hitherto exclusively been driven mechanically, for instance, by means of eccentrics or gear transmissions. This fact is the more remarkable taken on line XXI-XXI well suited to satisfy all requirements to which so that the dead run times can be reduced to a minimum.

The reason why shaping machines with too] holder slides which are reciprocable transversely to the planing direction hitherto have without exception been operated mechanically, is that it is not possible in a reliable way to supply working fluid from a hydraulic stationary plant to the operating cylinder for the tool holder, which is movable in its slide lengthwise of the support. Elastic tubes have failed completely in shaping machines, because the frequent reversals of the slide movements involve a constant alternation between planing pressure and no load in the elastic tubes, so that a breathing is created in the tubes whereby they become unusable in a very short time.

The known hydraulic driving arrangements for shaping machines, consisting of pump, control devices and oil tank, are also so bulky that only a stationary mounting of same is possible. No attempts have been made to depart from this stationary arrangement and there has also not been any reason for doing so, since such an arrangement has not involved any special difiiculties.

A particular deficiency of the mechanically driven shaping machine, the tool holder slide of which is reciprocated transversely to the planing direction, lies in the fact that the mechanical drive for the tool holder is arranged in the central part of and over the entire length of the support, so that the upper part of its top must be cut through entirely. This deficiency has only a limited effect in those shaping machines in which the feed and high speed movements of which are caused by the table, since the support naturally is short. In the case of shaping machines with tool holder slides reciprocable transversely to the planing direction, the support is so long that the stability of the entire machine is reduced by cutting through the tops of the support. This however impairs the precision of working of the machine and renders it impossible to load the same to give a high output.

The end of the tool holder slide opposite to that carrying the tool usually projects somewhat beyond the support in order that the tool holder is reliably guided. It is preferred to arrange the hydraulic drive on the lower side of this end of the slide. In this way the driving apparatus is arranged in a space, which in known machines is also present but is not utilised.

The members for the operation of the pump and the control device are suitably arranged on the end of the slide adjacent the tool. Compared with the known mechanically driven shaping machines, the tool holder slide of which is reciprocable transversely to the planing direction, the invention also possesses the advantage that a very simple connection may be used between these members and the pump and. the control device. Therefore, in contrast to the known machines, no complicated intermediate parts, such as flexible shafts and the like are required, but only short and simple transmission elements, such as rigid shafts, gearings and levers.

The shifting of the auxiliary control valve, by means of which the slide is moved for reversing the tool holder movement, is suitably performed by means of a shaft, which is rotatably arranged in the slide and the end of which adjacent the attending face is connected with a lever which is movable between two stop adjustably fixed to a circular disc. This disc is in some way or another operatively connected to the reciprocating tool holder. The disc may for instance be equipped with a worm wheel, which is engaged by a worm shaft rotatably arranged in the tool holder slide and carries a gear, with which a rack meshes which is fixed to the tool holder in the direction of its movement. The gear ratio between the rack on the tool holder and the worm on the disc is so chosen that the longest stroke of the tool holder does not fully correspond with a revolution of the disc, since sufficient space must be provided for the stops.

The pump is preferably constructed as a rotary piston pump, the delivery of which is regulated by altering the stroke of the pump piston by deflecting the pump body. In the present invention it has been found particularly advantageous to effect the regulation of the pump by means of a small auxiliary electro-motor. It is also possible to transmit the movement for the deflection of the pump body mechanically to the attending face of the tool holder slide. However in view of the restricted space available it has been found advantageous to use electrical transmission.

In the following the invention will be particularly described with reference to the drawings.

Fixed on the support I are two tables 2 and 3, Fig. 4, to which the workpiece or pieces are clamped in any known manner. Arranged on the upper side of the support are two slides 4 and 5 which are displaceable in the longitudinal direction and serve as carriers for the tool holders 6 and I. Both holders are arranged to reciprocafe on the slides in such a. manner, that their direction of movement is perpendicular to that of the slides. The slides 4 and 5 project somewhat beyond the support on the side of the support remote from the tables 2 and 3. On the lower side of these projecting ends of the tool holder slides are arranged casings 8, 9, Figs. 1 and 5, in each of which a pump I0, I I and a control device l2, l3 respectively are located. The pumps are driven by electric motors l4, 15 respectively which by means of flanges are fixed to the corresponding casings 8 and 9.

The two slides 4 and 5 with their tool holders 6 and 1 may be arranged so that they present identical mirror images, that is with the tool holders practically adjacent to each other. In the arrangement of the parts care should be taken that the slides can move as close to each other as possible. As particularly shown in Fig. 5, some details of the slides 4 and 5 are of different form. The embodiment represented by the slide 5 is however preferred so that this slide will be described more fully in the following. Apart from the relations between the electromotor and the pump, the difference between the two embodiments resides particularly in the arrangement of the oil container. As shown in the right part of Fig. 5, and in Figs. 2 and 6 to 10, the casing 9 which accommodates the pump II, the driving motor l5 and the control device, simultaneously serves as an oil collector vessel. The

pump draws in driving fluid from this vessel and the excess driving fluid 'flows back into the same. A special collector vessel Figs. '1 and 5, which is fixed on the support I is provided for the drive of the tool holder 6, and into which a tube I51 projects, which during the advance of the slide 4 reciprocates in the vessel |5| and which is fixed to the container B.

The tool holders 6, 1 are reciprocated by means of the fluid delivered from the pump. For this purpose a cylinder l6, Figs. 1 and 23, is fixed in each of the two slides 4, 5 and a piston I1 is arranged in this cylinder which is reciprocable in the direction of the stroke of .the tool holder. The piston I1 is, in known manner, rigidly connected with the tool holder so that the exposed area of one side of the piston is larger than that of the other side. Both sides of the piston communicate through tubes 41 and 5|! with the control device |2 or I3 and thus also with the pump I6 or II. The control device l2, Fig. 1, is mounted horizontally on the pump I6, while the control device i3 is mounted vertically on the pump N, Fig. 5.

The forward stroke of the tool holder is accomplished by supplying pressure fluid to the chamber 99, Fig. 1, of the cylinder facing the full crosssectional area of the piston I1 and the other end of the cylinder is connected with the outlet vessel or the cylinder space 99. The return stroke of the piston, which, as is known, requires less force, is accomplished by charging the cylinder side H10, the effective piston surface of which is reduced by the area covered by the piston rod l8. The cylinder space 99 is connected with the outlet vessel in corresponding manner by means of the control device.

Provided in the control device I2 or |3 are three control slides, Figs. 13 to 17, namely the slide 18 by means of which the piston H of the working cylinder I6 is reversed, the slide 19 by means of which the working cylinder [6, I1 is placed into and out of action and the auxiliary slide 85 which controls the main slide 18 and which in a manner hereinafter described is operated by the reciprocating tool holder 6 or 1 by means of adjustable stops.

The casing 8|, Figs. 13 to 17, for the control device has three parallel bores, which are lined with bushings 82, 83 and 84. 18 is longitudinally displaceable in the bore 82 and the control slides 19 and 86 are arranged in similar manner in the bores 83 and 84.

The control device shown in Figs. 13 to 17 operates in the following manner:

The return stroke side of the working cylinder l6 having the smaller piston surface communicates with the conduit 41, and the forward stroke side of the working cylinder [5 communicates with the conduit 50, Fig. 1. In Fig. 13 the central control slide 16 is shown in the position it assumes when the machine is operating. The pressure fluid from the pump enters the casing 8| of the control device through the opening 46,

Fig. 16, and flows through the bores '43, the channel 4| and the slots 42 into the annular space 95 of the main control slide 18. The pressure fluid thereupon flows through the slots 52, the channel 5| and the conduit 5!! into the righthand side of the cylinder.

From the channel 5| the pressure fluid also flows through the slots 56, Fig. 13, into the annular space 38 of the auxiliary control valve 80, and from there it flows into the space 22 of the main control valve 18 through the slots .54 and The control slide the channel 51. Thus, the valve 18 is securely held in its lefthand position against the action of the spring 9| by the pressure exerted by the pressure fluid on the right side of the piston 81.

From the left side of the cylinder, which in the described example corresponds with the return stroke of the machine, the pressure fluid flows through the conduit 41, Fig. 13, the channel and the slots 61 to the annular space 34 of the auxiliary control valve 80. From the space 34 the pressure fluid flows through the slots 63, the channel 62 and the slots 64 and leaves the device through the longitudinal grooves 25 in the control slide 19.

The delivery side of .the pressure fluid pump also communicates with the annular space 36, Fig. 13, of the preliminary control valve through the channel 4| and the slots 44. The pressure fluid thereupon flows through the transverse bores 15 in the valve 86, the longitudinal bore 16 and the transverse bores 11 into the annular space 38. From this space 38 the pressure fluid flows through the slots 54 and the channel 51 into the space 22, in which it acts upon the piston 81 of the valve 18.

When the machine is to be reversed, the auxiliary control valve 86 is moved to the right, Fig. 13, in any known manner. At the same time that .the piston 21 closes the slots 61 in the bushing 46,

the piston 3| will cover the slots 56, whereby the channel 5| is brought into communication with the longitudinal slots 25 in the piston valve 19 and with the outlet container through the annular space 31, the slots 66, the channel 59 and the slots 6|. The piston 32 of the preliminary control valve 85 also uncovers the slots 55 and the channel 58, whereby communication is established between the space 22 and the outlet container through the slots 53, the channel 51, the slots 55 and the annular space 38.

The spring 9 I, Fig. 13, of the main control valve 18 is now no longer opposed by any forc and will therefore move the main control slide 18 to the right, overcoming the frictional resistance. The spring is associated in its action in that the annular space 35 of the valve 80 now communicates with the slots 44 in the bushing 46. Thus the delivery side of the pump is connected by means of the bores 12, 13 and 14 with the space 33, which at this moment is in register with the slots 1|. The pressure fluid will therefore flow through these slots, the channel '68, the radial slots 69 and the longitudinal slots 1!] into the annular space 96 and acts upon the left side of the piston 85.

The pressure fluid pump now communicates with the left side of the cylinder through the channel 4|, the slots 42, the space 94, the slots 49 and the conduit 41.

When reversing from th rearward stroke to the forward stroke the auxiliary control valve 86 is again moved into the position shown in Fig. 13. The pressure fluid flowing from th right side of the cylinder through the opening 56 will accumulate in the channel 5| and the annular space 38, for the reason that the slots 66 and the channel 59 are shut off by the piston 3|. The pressure of the accumulated fluid is transmitted through the slots 54, the channel 51 and the slots 53 to the space 22 and the main control valve 18 is moved to the right against the pressure of the spring 9| by the pressure acting upon the right side of the piston 61. Thi elfect i augmented due to the fact that the space 22., as described, communicates directly with the delivery side of the pressure fluid pump through the channel 5! and the bore I6.

The central control valve I9, Fig. 13 can be displaced longitudinally until the annular space 23 communicates with the slots 64. In this position the annular space 23 is connected by means of the short longitudinal slots 24 with th bores 43, which communicate with the delivery side of the pressure medium pump. In this way the pressure fluid flowing from the left side of the cylinder will flow through the channel 65, the annular space 34, the channel 92, the slots 6 the annular space 23, and the longitudinal slots 24 towards the delivery side of th pressure fluid pump.

The pump used may be of any known circulating pump type. The details of the pump chosen for this embodiment of th invention are shown in Figs. 11 and 12. The electric motor I4 or I5,

Fig. 5, drives the shaft IOI, Fig. 11, which is enbody I04 is rotatably arranged on the rod 153,.

Fig. 11, which is fixed in the swingable frame I52 and is connected with the driving shaft MI by means of a shaft I54, which is coupled to the driving shaft IOI as well as the cylinder body I 04 by Cardan joints. Arranged in the cylinder bores I09 are longitudinally displaceable pistons I01, th ball-shaped ends of which are received in the bearing blocks I03. By turning the cylindrical body I04 about the axis I05, the stroke of the piston I0! is altered. When the cylinder I04 coincides with the longitudinal axis of Fig. 12, the delivery of the rotary piston pump is zero. The more the cylinder is deflected, the larger becomes the stroke and the delivery.

I59, Fig. 11, denotes the suction side and I60 the pressure side of the pump. If the control device is to be located directly on the pump it must be placed on the side ISI.

The levers for the operation of the slides I9 and 80, Figs. 13 to 17, of the control device are arranged at the end wall I 9, Fig. 19, of the tool I holder slides 4 and 5. The control slide I9 for starting and stopping the machine is moved by the rod 30 by mean of th levers I09, IIO, Fig. 19. By means of the lever I09 and intermediate links the slide I9 can be so turned that the longitudinal channels are in communication with the bores 43 in the bushing 45. In this way the inlet opening 40 is brought into direct communication with th opening 20 which leads to the outlet vessel, whereby the piston is stopped since the working piston I'I, Fig. 1, no longer delivers pressur fluid.

By means of the lever II9 the control valve I9 can be displaced longitudinally in such a manner that the annular space 23 will be above the slots 64. In this way in the manner described above, the pressure fluid flowing out from the return side I00, Fig. l, of the working cylinder I6 will flow to the delivery side of the pressure fluid pump, so that the velocity of the forward stroke of the machine is increased.

The rod III, Figs. 13 and 20, of the auxiliary control slide 80 is constructed as a rack-bar and thus the teeth thereof mesh with a gear wheel H2.

Since the control device of the pump in the preferred embodiment of the invention shown on the right half of Fig. 5 is arranged vertically, the shaft II3 of gear wheel II2 may be so arranged that its elongation can be received in a bearing in the end wall I9 of the tool holder slide 5. In a position deviating from the vertical position, for instance with a horizontal arrangement of the control device as shown on the left hand side of Fig. 5, a number of transmission members must be arranged between the shaft I I3 and the actuating shaft which is supported in the end wall I9. Fixed on the end wall side of the rotatable shaft H3 is a lever II4, Figs. 4, l8 and 20, which is movable within the range of a rotatable circular disc II5, which is spaced from the shaft H3 and carries two slidable and adjustable stops H6 and III on the peripheral portion H8. The disc I I5 also carries a worm wheel I I9 which meshes with a worm I20, th rotatable shaft I 2| of which is journalled in the tool holder slide and carries a gear wheel I22, Fig. 22. This gear wheel I22 meshes with a rack I23 which is fixed to the tool holder. The ratio with which the transmission members transmit the movement of the tool holder 6 or I to the disc H5 is so chosen that the longer stroke of the tool holder does not correspond fully to one revolution of the disc. By adjustment of the two stops H6 and I II the length and position of the tool holder stroke may be adjusted as desired.

Also arranged on the end I9 of one of the two tool holders 4 or 5 is a speed indicator I55, Fig. 21, which indicates the velocity of the tool holder.

Also the lever II4, by mean of which the circulating pump is deflected and the delivery of the pump is regulated, is arranged on the head of the tool holder slide. In this embodiment the pump is deflected by means of an auxiliary electric motor. This arrangement is shown in detail in Figs. 6 to 8.

As described in the foregoing the pump II, Fig. 6, and the control device (not shown) are arranged in the casing 9. The pump motor I5 is fixed to the casing by means of flanges.

The swingable frame I52, Fig. '7, with the cylinder body I04 is, as described, tiltable about the axis I05, Fig. 12. This frame I52 carries on one side a small bracket I25 on which is located a roller I24 which is loaded by a piston I21, which is arranged so as to be longitudinally displaceable in the cylinder body. The working chamber I28 of the piston I21 communicates with the oil circuit at a suitable point which during the forward stroke of the tool holder is under pressure but during the return stroke communicates with the outlet vessel. The chamber I28 may for instance be connected, not shown, with the chamber 22, Figs. 13 and 17, of the control device. The piston I21 attempts to hold the frame I52 with the cylinder body I04, Fig. 11, on the central longitudinal axis of the pump, i. e. in a position in which no fluid is delivered. A spring I29, one side of which is secured on the frame I 52 and the other end is attached to a suitable point on the casing 9, tends to turn the frame I52 with the cylinder body I04 and to set it for maximum pump delivery.

The delivery during the forward stroke of the pump is altered by means of a cam I35, Fig. 7, which is keyed to a shaft I3I, rotatably arranged in a cover I32 of the casing 9. Fixed on the shaft I3I or on a collar of the cam I30 is a worm wheel I33, which cooperates with a worm I34, Fig. 8, the shaft I35 of which is rotatably mounted in the cover I32. This shaft I35 is also provided with a worm wheel I35, with which a worm I31 meshes, the shaft I38 of which is parallel to the shaft I3I and to which the shaft of an auxiliary electric motor I33 is secured by means of a flange. The motor I39 is fixed in any suitable manner to the cover I32.

The motor I39 is reversible, so that the cam I33 can be rotated in either direction.

By corresponding adjustment of the cam I33 the delivery on the forward stroke can be altered as desired. The cam I30 is arranged within the range of a stop Hi3 fixed to the head of the piston I21. The piston can therefore only deflect the cylinder body I34, Fig. 11, as far as the position of the cam I35 allows. Due to the two worm wheels arranged in series the transmission ratio between the auxiliary motor I33 and the shaft I3I is very high, so that a considerable number of revolutions of the auxiliary motor i355 corresponds to only a small deflection of the shaft I3I.

The cylinder chamber I28 iswithout pressure during the return of the tool holder, so that the spring I23 swings the frame I52- and with it the cylinder body I34 into the position which corresponds to maximum delivery. By means of an additional cam Hit, Fig. 8, the shaft I52, Fig. '1, of which is also rotatably mounted in the cover I32, it is also possible to alter the velocity of the return stroke. For this purpose the cam I l! engages the rear part of the stop Mil, so that the spring E23 is only able to deflect the cylinder body in accordance with the position of the cam I lI. Since in the usual working operations of the shaping machine such alteration of the velocity of the return stroke is seldom necessary, in the embodiment shown in the adjustment wheel for the cam I! is fixed directly to the shaft 552. The movement is thus not transferred to the end IQ of the tool holder slide.

For the control of the auxiliary motor I39, a switch I43, Fig. 3, is arranged on the front side of the appertaining tool holder slide.

The top I55, Fig. 1, of the support I has no interruptions. The slides 4 and 5 are guided along the support I by the guides 5 and I45. While the guide M5 is arranged in known manner on the front side of the table, the guide I35 is located substantially in the middle of the support top and is held by a slightly tapered moulding m. The conical moulding can be adjusted in known manner by means of the screws M8.

To cause the advance movement a rack I69 is also fixed to the support I. The teeth of this rack mesh with a toothed gear I5, 1, rotatably arranged in the slide I or 5. The automatic advance is preferably carried out hydraulically. For this purpose a piston device may be used to which pressure fluid is admitted in the cycle of the forward and return stroke of the tool holder. In the embodiment shown, the movement of the reversing slide 18, Fig. 13, can be utilised with particular advantage for the drive of the members which cause the automatic advance of the tool holder slide.

Each of the tool holder slides t or 5 may be moved manually or by means of a special electric motor I58, Fig. 21.

In the embodiment shown in Figs. 18-23 the control device I3, Fig. 23, is no longer mounted directly on the pump 5 I but is incorporated within the slide 5. The feed movement, i. e. the displacement of the slide 5 on the support I is effected by means of a rack-bar I49, Fig. 21, which is rigidly secured to the support and in which engages a pinion I53 rotatably mounted on the slide. This pinion can be rotated in three different ways:

1. Automatically from the main valve 18 of the control device (automatic feed),

2'. By means of the reversible electric motor I58 secured on the slide 5 (high-speed movement or mechanical feed movement),

3. Manually.

The central control valve 19 may again be both displaced longitudinally as Well as rotated by means of two levers I 09 and III], Fig. 18. The auxiliary valve is moved by means of a stop disk II5 which is constructed similarly to that of the embodiment of Figs. 1-17.

Secured to the control valve body 13 is a rod 65 on which is mounted the spring SI (Fig. 13) which bears at one end against a stop 95, Fig. 20, rigidly connected with the rod 86 and at the other end against a bearing body 88', which constitutes a rigid component of the casing of the slide 5. Journalled in this bearing body is a shaft 83, the axis 92 of which is at right-angles to the axis of the shaft 85. The shaft 53 carries a gear wheel, the teeth of which engage in the teeth of a rack-bar 33 formed on the shaft 86.

Secured on that end of the shaft 89 which terminates above the slide 5, is a disc 91, Figs. 19 and 22, provided with a diametrally extending groove 2|. Displaceable in this groove is a block 26 which can be moved to and fro in the slot by means of a threaded shaft .28 and an adjusting wheel 23.

Journalled at some distance from the disc 91 towards the rear end of the slide is a ratchet wheel 33, Fig. 19, which, in the present case, has a particular construction. The pawl 48 is, in this case, rotatably arranged about two parallel pins I63, I64. One pivot I64 is engaged by a rod I65 which connects the pawl 53 with the block 25. The other pivot I53 is mounted on a lever I62 which is freely mounted on the shaft I66 of the ratchet wheel 35. To avoid rearward rotation of the ratchet device during idle movement of the ratchet 3!], :38, a further pawl 161 engages in the teeth of the ratchet wheel 39.

The shaft I53 of the ratchet wheel 30 is journalled on the top of the slide 5 and carries within the slide a bevel gear wheel IE3, Fig. 18, which engages two bevel wheels I1I, I12 freely mounted on the shaft I10, Fig. 2%). The shaft 515 is parallel to the shafts 86, 38 and I5! of the three control valves.

Mounted for rotation on the axis I18 are three shafts I68, I13, I14, Fig. 20, which can be coupled together by means of separate coupling devices. Interposed between the two shafts I68 and I13 is a coupling device I15 which has a coup-ling member I16 longitudinally displaceable on the shaft I13. The coupling member 15 is provided with coupling teeth on the outwardly facing radial surfaces. The coupling teeth provided on the righthand side can engage in corresponding teeth on a sleeve I11 which is keyed on the lefthand end of the shaft I58. The teeth of the coupling member I16 on the lefthand side can engage in corresponding teeth on a sleeve I18 which is freely rotatable on the shaft I13 and is rigidly connected with a worm wheel 119. The teeth of this worm wheel are engaged by a worm I which is driven by the reversible electric motor I58 mounted on top of the slide 5.

Mounted in the interior of the slide 5 on a shaft IBI, Fig. 21, which carries the gear wheel I50 engaging in the rack bar I49 on the support 

